Great insights, Jason. I agree with you on all of this...
I was going to suggest that the Dolphins pennant is from a different source than the others (based on being cloth vs. felt, and rare vs. common).
But after looking at it again, I believe you are right.... same maker (AdFlag). This pennant has always cracked me up. Mahi Mahi were sometimes referred to as "Dolphin Fish". Obscure as this is, I can't believe the artist actually depicted the Dolphin Mascot that way (and that an AdFlag exec actually approved it).
Here's another pennant that definitely belongs in that same grouping...